Description of problem:
LDAP Group Lookup string needs to be changed to External Auth group lookup in all places when external auth is configured.

Version-Release number of selected component (if applicable):
5.7.0.7-beta1.20161025153249_9376fbd

How reproducible:
always

Steps to Reproduce:
1. Login as admin and change the auth mode to "External Auth(httpd)"
2. navigate to Groups->Add new group, Observe that the check box text is set correctly as "(Look Up external auth groups)"
3. Observe the text field "LDAP Group Look Up" in the same page. when auth mode is changed to external auth, this field may needs to be updated to "external auth Groups Look Up".

Actual results:
LDAP Group Lookup string is set in some places even when external auth is configured.

Expected results:
LDAP Group Lookup string needs to be changed to External Auth group lookup in all places when external auth is configured.